Wafer edge inspection

ABSTRACT

In one embodiment, a surface analyzer system comprises a radiation targeting assembly to target a radiation beam onto a surface; and a reflected radiation collecting assembly that collects radiation reflected from the surface, wherein the reflected radiation collecting assembly comprises a mirror to collect radiation reflected from the surface.

RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 11/123,923, filed May 6, 2005, entitled Wafer Edge Inspection,the disclosure of which is incorporated herein by reference.

BACKGROUND

The subject matter described herein relates to surface inspectiontechniques, and more particularly to wafer edge inspection.

Semiconductor materials may be inspected for defects such as, e.g.,surface imperfections, particles, irregularities in the thickness ofthin film coatings, and the like, which may hamper the performance ofthe semiconductor material. Some existing inspection systems direct abeam of radiation on the surface of the semiconductor material, thencollect and analyze light reflected and/or scattered from the surface toquantify characteristics of the surface. Additional inspectiontechniques are desirable. In particular, it is desirable to inspect theedge or near edge of semiconductor wafers, compound semiconductorwafers, transparent wafers or thin film disks for defects such asparticles, scratches, pits, mounds, cracks, blisters, missing films,chips, and other defects.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is described with reference to the accompanyingfigures.

FIG. 1 is a schematic illustration of various optical components of anembodiment of an apparatus for wafer edge inspection.

FIG. 2 is a schematic illustration of one embodiment of an apparatus forwafer edge inspection.

FIG. 3 is a schematic illustration of one embodiment of an apparatus forwafer edge inspection.

FIG. 4 is a schematic illustration of various optical components of anembodiment of an apparatus for wafer edge inspection.

FIG. 5 is a schematic illustration of various optical components of anembodiment of an apparatus for wafer edge inspection.

FIG. 6 is a schematic illustration of various optical components of anembodiment of an apparatus for wafer edge inspection.

DETAILED DESCRIPTION

Described herein are exemplary systems and methods for wafer edgeinspection. In the following description, numerous specific details areset forth in order to provide a thorough understanding of variousembodiments. However, it will be understood by those skilled in the artthat the various embodiments may be practiced without the specificdetails. In other instances, well-known methods, procedures, components,and circuits have not been described in detail so as not to obscure theparticular embodiments.

Various methods described herein may be embodied as logic instructionson a computer-readable medium. When executed on a processor the logicinstructions cause a processor to be programmed as a special-purposemachine that implements the described methods. The processor, whenconfigured by the logic instructions to execute the methods describedherein, constitutes structure for performing the described methods.

FIG. 1 is a schematic illustration of one embodiment of an apparatus forwafer or disk edge inspection. Various optical testing components andtechniques for surface inspection are described in U.S. Pat. Nos.6,665,078, 6,717,671, and 6,757,056 to Meeks, et al., the disclosures ofwhich are incorporated herein by reference in their entirety. Any of theassemblies and techniques described in these patents may be used in asurface analyzer for wafer edge inspection.

One embodiment is adapted to perform film thickness measurements,surface roughness measurement, reflectivity measurement, magneticimaging, and optical profiling using radiation in the optical spectrum.In alternate embodiments radiation outside the optical spectrum may beused. More particularly, FIG. 1 depicts an optics assembly capable ofperforming that includes a combined reflectometer, scatterometer, phaseshift microscope, magneto-optic Kerr effect microscope and opticalprofilometer. This embodiment is capable of detecting and classifying awide variety of defects at a wafer or disk edge or near edge.

Wafer 120 includes an upper surface 122, a lower surface 124, and anedge surface 126, which may be substantially flat or curved when viewedin a cross-sectional profile. In the embodiment depicted in FIG. 1, thewafer edge surface is curved when viewed in cross-sectional profile.

A surface analyzer assembly 110 is positioned to direct radiation onto asurface of wafer 120. In the embodiment depicted in FIG. 1, surfaceanalyzer assembly 110 includes a laser diode 112, an optional polarizer114, an optional half-wave plate 116, and a focusing lens 118 fordirecting radiation onto a surface of wafer 120. These components targetradiation from the laser diode onto the surface of wafer 120, and hencemay be considered a radiation targeting assembly. In alternativeembodiment polarizer 114 and half-wave plate 116 may be omitted.

Surface analyzer assembly 110 further includes a collecting lens 130 anda photomultiplier tube (PMT) 132. These components collect radiationscattered by the surface of the wafer 120, and hence may be considered ascattered radiation assembly. In alterative embodiments the PMT 132 andcollecting lens 130 may be replaced with an integrating sphere or anellipsoidal mirror together with a PIN photodiode or avalanchephotodiode.

Surface analyzer assembly 110 further includes a collimating lens 136, awobble reduction lens 137, a quarter wave plate 134, a Wollaston prism138 rotated at 45 degrees to the plane of incidence, and two quadrantdetectors 140, 142 available from Hamamatsu, Inc. In another embodiment,detectors 140 and 142 may be PIN photodetectors also available fromHamamatsu, Inc. The embodiment shown in FIG. 1 utilizes quadrantdetectors so that the slope of the surface may be measured. The surfaceslope may be integrated to produce the surface profile. These componentscollect radiation reflected from the surface of wafer 120, and hence maybe considered a reflected radiation assembly. The wobble reduction lens137 is a converging lens. In alternative embodiments the wobblereduction lens 137 and the collimating lens 136 may be combined into asingle lens. The wobble reduction lens is chosen so that its focallength is substantially equal to the distance between wobble reductionlens 137 and the quadrant detectors 140 and 142. When this is done thesurface slope measured at the quadrant detectors will be minimized. Thatis, the system will be most tolerant of wobble of the wafer. Anotherembodiment would position the detectors 140 and 142 at a distanceslightly longer or shorter than the focal length of the wobble reductionlens 137. In this case the system would have some sensitivity to bothwafer wobble and to surface slope.

In one embodiment surface analyzer assembly 110 uses a multi-mode,multi-wavelength laser diode 112 which is available from Rohm Co., LTDKyoto, Japan as model number RLD-78MV and a polarizer 114 which isadjusted for P polarization and improves the extinction ratio of thelaser. The radiation may be of any wavelength. In one embodiment a 405nm violet source available from Coherent, Inc may be implemented. Inanother embodiment a 635 nm source may be implemented. The mechanicallyrotatable half wave plate 116 is available from CVI Laser Corp. and canbe used to rotate the polarization between 45 degrees, and P or Spolarization's. Alternative techniques for rotating the polarizationinclude rotating the laser diode 112 or to use a liquid crystalpolarization rotator such as model LPR-100 available from MeadowlarkOptics, Frederick, Colo. The latter embodiment has the advantage ofbeing a purely electronic means of polarization rotation and as a resultthere is no possibility of beam movement when the polarization isrotated.

Focusing lens 118 creates a small spot on the surface of a wafer 120.The PMT 132 and collecting lens 130 are used to measure the scatteredlight for the purposes of computing the surface roughness, measuringdebris, detecting stains, cracks, scratches, delaminations, blisters orcorrosion on the disk or wafer 120 surface or edge 126 or near edgeregions.

After reflecting from the disk, the beam passes through the collimatinglens 136, the wobble reduction lens 137, and a quarter-wave plate 134.The beam is then polarization split with a Wollaston prism 138 availablefrom CVI Laser Corp., for example, and each polarization component isdetected with separate photodetectors 140, 142. The plane of theWollaston prism (the plane of the S and P components) may be adjusted atsubstantially 45 degrees to the plane of incidence. The first mixedcomponent of the beam (which includes both P and S components withrespect to the plane of incidence) is directed to a detector 140 and thesecond mixed component (which includes both P and S components withrespect to the plane of incidence) is directed to a second detector 142.In one embodiment the photodetectors 140, 142 may have a diffuser placedin front of them to reduce the residual position sensitivity of thephotodiodes. The difference between the intensity measured by thephotodetectors is proportional to the cosine of the phase differencebetween the first and second mixed components coming from the Wollastonprism. As a result this instrument can get different types ofinformation when used in different modes.

When the polarization is adjusted to P, the P specular and P scatteredlight is measured resulting in sensitive measurements of carbonthickness (or any simple layer thickness) and carbon wear. The Pspecular signal is obtained by rotating the half wave plate 116 so thatthe polarization output from the half wave plate is P polarized. The Pspecular signal is given by the sum of the signal from 140 and 142. Whenthe polarization is adjusted to 45 degrees (exactly between P and Spolarization) the instrument is most sensitive to measurements of thephase change induced by changes in the thickness of the thin films onthe disk or wafer surface. In the phase shift mode the instrumentmeasures lubricant, carbon, or other film thickness changes on thin filmdisks or wafers. The phase shift is measured by taking the differencebetween the signals measured at 142 and 140. This gives an output thatis proportional to the cosine of the phase difference between the firstand second mixed components of the wave. The orientation of the quarterwave plate 134 is adjusted to optimize the sensitivity to lubricant,carbon wear, other film thickness changes or changes in phase due to thepresence of defects. The individual components may also be measured;that is, the first and second mixed components of the 45 degreespolarized light. These are measured simultaneously with the phase shiftand the scattered light.

When the half wave plate is rotated so that the polarization is adjustedto S polarization the instrument will be able to measure the S specularand the S scattered light and, as a result, obtain the surface roughnessand other properties of the sample. The S specular signal is given bythe sum of the signal from 140 and 142. The angle of incidence shown inFIG. 1 is 58 degrees but angles greater or less than 58 degrees willwork as well. The longitudinal Kerr effect can be measured by operatingthe instrument in any of the linear polarization's, i.e., P, S or 45degrees. Rotating the quarter wave plate 134 to achieve maximumsensitivity to the magnetic pattern optimizes the Kerr effect signal.The orientation of the quarter wave plate which optimizes the Kerreffect may be different from that which optimizes for lubricant andcarbon sensitivity. As a result the quarter wave plate is made to beremovable, for example, so that two different and separately optimizedplates can be used for the different applications. A differentembodiment would have a miniature motor to rotate the orientation of thequarter wave plate so as to optimize the signal for the Kerr effect,lubricant, carbon or defect detection mode. Different polarizations mayrequire a different quarter wave plate adjustment to achieveoptimization. When in this mode the instrument functions as a Kerreffect microscope. In one embodiment the S polarization is used to imagethe longitudinal Kerr effect. When the surface is imaged by the OSA in Slinear polarization the reflected light has its polarization convertedto elliptical polarization whose major axis is rotated depending uponthe orientation of the magnetization upon the thin film disk. This Kerreffect signal is detected by measuring the two signals coming from thepolarization beam splitter and subtracting them. This will give a signalwhose sign is related to the direction of the magnetization and whoseamplitude is proportion to the magnetization.

The data collected by the scattered radiation collection assembly andthe reflected radiation collection assembly is fed to a processingmodule that includes a processor 160, a memory module 162, and an I/Omodule 164. Processor module comprises logic instructions that enablethe instrument described in FIG. 1 to simultaneously measure the profile(height and depth) of the surface, the S and P components of thereflectivity, the phase shift between the P and S waves and thescattered light. It is also capable of measuring the Magneto-optic Kerreffect.

The measurement of the phase shift between the S and P components of theoptical wave requires a means to stabilize the long-term phase drift ofthe diode laser. This can be accomplished by the use of a referencemirror. The reference mirror is a stable surface such as a gold mirror,a section of a thin film disk, or section of a silicon wafer. Thereference mirror is calibrated when the instrument is first set up bymeasuring and recording the phase shift of the reference mirror. Attimes after the initial calibration of the instrument the referencemirror is measured prior to a measurement of the sample. Any deviationof the reference mirror reading from the initial reading is recorded andsubtracted from the measurement of the sample readings. This insuresthat the phase shift reading from the surface under measurement willremain stable over time. The same procedure can also be applied to themeasurement of the S specular and P specular signals. In this case whenthe instrument is calibrated the values of the P specular and S specularsignals measured on the reference mirror are recorded and deviationsfrom these values are used to correct the specular data. This removesany drift from the P and S specular signals.

The above discussion is relating to an instrument, which has an angle ofincidence that is near 60 degrees from the vertical. Similar ideas canbe applied to a machine operating at angles less than or greater than 60degrees. When the angle of incidence changes the interpretation of thevarious quadrants of the histogram will change.

FIG. 2 is a schematic illustration of one embodiment of an apparatus forwafer edge inspection. During the inspection process a wafer 220 may berotated about a central axis on a spindle 228, which may be connected toa suitable motor or other drive assembly for inducing rotational motionto the spindle. A first drive assembly including, e.g., a motor formoving the head in the horizontal direction 250 moves a surface analyzerassembly 210 as described herein or as described in U.S. Pat. Nos.6,665,078 , 6,717,671 and 6,757,056 over the wafer surface, generatingdata about various characteristics of the surface. A second driveassembly including, e.g., a rotational motor connected to the surfaceanalyzer assembly 210 by a suitable linkage 254 provides rotationalmotion to move the surface analyzer assembly 210 around the edge surface226 of the wafer in a path illustrated by the dashed arrow in FIG. 2.

In one embodiment the motor producing the linear motion 250 and therotational motor 252 cooperate to maintain a substantially fixeddistance between the surface analyzer assembly 210 and the respectivesurfaces 222, 224, 226 of the wafer as the surface analyzer assembly 210rotates about the edge surface 226 of the wafer. The edge of the wafer226 is not necessarily in the shape of a semicircle but may in generalbe any type of shape. If motors 250 and 252 are operated in acooperative manner then the head 210 may be kept at a fixed distanceabove the wafer edge regardless of the shape of the edge. Optionally,the motor producing the linear motion 250 can cause the surface analyzerassembly 210 to traverse the top 222 and or bottom surface 224 of wafer220, permitting the surface 224 or 222 to be scanned for defects.

In one embodiment the apparatus comprises an assembly for centering thewafer on the spindle, which reduces the lateral variation (or “wobble”)in the edge of the wafer as it rotates about a central axis. FIG. 3 is aschematic illustration of a wafer edge inspection system illustrating anassembly for centering the wafer 320. Referring to FIG. 3, a wafer 320rotates about a central axis on a spindle 328. Wafer 320 may rotate ineither direction, as illustrated by the dual-headed arrow. An surfaceanalyzer assembly 310 scans the edge 326 of wafer 320, as describedabove.

Three positioning heads 360 a, 360 b, 360 c are positioned adjacentthree points on the outer edge 326 of wafer 320. In one embodiment thethree positioning heads 360 a, 360 b, 360 c are positioned at therespective vertices of an equilateral triangle circumscribed by the edgeof wafer 320. However, the positioning heads 360 a, 360 b, 360 c may beotherwise positioned.

The center of the triangle represented by positioning heads 360 a, 360b, 360 c corresponds to the center of the spindle 328. In oneembodiment, the positioning heads 360 a, 360 b, 360 c may be configuredto transfer their (x, y) coordinates to the processing module (see, FIG.1), which calculates the (x, y) coordinates of the center of the wafer320. The wafer 320 may then be moved such that the center of the wafer320 corresponds to the center of the spindle 328. In one embodiment, oneor more of the positioning heads 360 a, 360 b, 360 c includes a pushingmechanism such as, e.g., a servo-mechanical plunger to position thewafer 320 over the center of the spindle.

In one embodiment the positioning heads 360 a, 360 b, 360 c are adaptedto communicate their respective (x, y) coordinates to the processor 160,which calculates the (x, y) coordinates of the center of the wafer fromthe positions of the positioning heads. The processor then determinesthe amount of movement necessary to position the center of the waferover the center of the spindle, and transmits instructions to thepositioning heads to move the wafer 320. In another embodiment the wafer320 and the positioning heads 360 a, 360 b, 360 c remain fixed inposition and the spindle 328 is moved.

In an alternate embodiment an apparatus for surface analysis may usemultiple surface analyzer assemblies rather than rotating a singlesurface analyzer assembly around multiple surfaces of a wafer. Forexample, a first surface analyzer assembly may scan an upper surface ofthe wafer, while a second surface analyzer assembly may scan an edgesurface of the wafer and a third surface analyzer may scan a lowersurface of the wafer.

FIG. 4 is a schematic illustration of various optical components of anembodiment of an apparatus for wafer edge inspection. Wafer 420 includesan upper surface 422, a lower surface 424, and an edge surface 426,which may be substantially flat or curved when viewed in across-sectional profile. In the embodiment depicted in FIG. 4, the waferedge surface is curved when viewed in cross-sectional profile.

A surface analyzer assembly 410 is positioned to direct radiation onto asurface of wafer 420. In the embodiment depicted in FIG. 4, surfaceanalyzer assembly 410 includes a laser diode 412, an optional polarizer414, an optional half-wave plate 416, and a focusing lens 418 fordirecting radiation onto a surface of wafer 420. These components targetradiation from the laser diode onto the surface of wafer 420, and hencemay be considered a radiation targeting assembly. In alternativeembodiment polarizer 414 and half-wave plate 416 may be omitted.

Surface analyzer assembly 410 further includes a collecting lens 430 anda photomultiplier tube (PMT) 432. These components collect radiationscattered by the surface of the wafer 420, and hence may be considered ascattered radiation assembly. In alterative embodiments the PMT 432 andcollecting lens 430 may be replaced with an integrating sphere or anellipsoidal mirror together with a PIN photodiode or avalanchephotodiode.

Surface analyzer assembly 410 further includes a reflecting mirror 436to collect light reflected from the surface 422 of wafer 420. In oneembodiment, reflecting mirror 436 may be implemented as a paraboloidreflector, e.g., a parabola of revolution. The paraboloid reflector 436may be positioned such that its focus is approximately coincident withthe focus of the laser and the axis of the paraboloid is tilted slightlyto allow room for further optical components. Radiation reflected fromparaboloid reflector 436 is collimated (i.e., divergence of the lightrays is removed).

The collimated beam exiting the paraboloid reflector 436 can move up anddown or from side to side (i.e., in and out of the page) due to theshape of the edge. Hence, light collected by the reflecting mirror 436is directed to a wobble reduction lens 437. The wobble reduction lens437 directs the collimated beam towards a fixed focus of the lens.

Radiation passing through the wobble reduction lens 437 is directed to aquarter wave plate 434, a polarizing beam splitter 438, and two quadrantdetectors 440, 442. The polarizing beam splitter 438 may be a polarizingbeam splitter cube, a Wollaston prism or some another suitablepolarizing beam splitter. In another embodiment detectors 440, and 442may be PIN photodetectors also available from Hamamatsu, Inc. Thesecomponents collect radiation reflected from the surface of wafer 420,and hence may be considered a reflected radiation collection assembly.

In one embodiment, the detectors 440, 442 may be placed at or slightlybehind the fixed focus of the wobble reduction lens 437. If thedetectors are placed slightly behind or in front of the fixed focus ofthe anti-wobble lens, then a profile (topography) signal may be detectedwith the quad detectors. In this manner the slope of the edge of thewafer may be measured. The profile of the edge may be determined byintegrating the slope of the edge.

In one embodiment, scattered light may be collected by removing aportion part of the reflecting mirror 436 to the right of the focus andplacing a PMT 432 (or avalanche photodiode or PIN photodiode) above thislocation. Optionally, a collecting lens 430 may be included.

Detectors 440, 442 and PMT 432 may have outputs connected to aprocessing module substantially as described in FIG. 1 to process theoutput substantially as described above.

FIG. 5 is a schematic illustration of various optical components of inan alternate embodiment of an apparatus for wafer edge inspection. Asurface analyzer assembly 510 is positioned to direct radiation onto asurface of wafer 520. In the embodiment depicted in FIG. 5, surfaceanalyzer assembly 510 includes a laser diode 512, an optional polarizer514, an optional half-wave plate 516, and a focusing lens 518 fordirecting radiation onto a surface of wafer 520. These components targetradiation from the laser diode onto the surface of wafer 520, and hencemay be considered a radiation targeting assembly. In alternativeembodiment polarizer 514 and half-wave plate 516 may be omitted.

Surface analyzer assembly 510 further includes a collecting lens 530 anda photomultiplier tube (PMT) 532. These components collect radiationscattered by the surface of the wafer 520, and hence may be considered ascattered radiation assembly. In alterative embodiments the PMT 532 andcollecting lens 530 may be replaced with an integrating sphere or anellipsoidal mirror together with a PIN photodiode or avalanchephotodiode.

Surface analyzer assembly 510 further includes a reflecting mirror 536to collect light reflected from the surfaces 522, 526, or 524 of wafer520. In on embodiment, reflecting mirror 536 may be implemented as anellipsoidal (that is, an ellipse of revolution) reflector. Theellipsoidal reflector 536 may be positioned such that its first focus isapproximately coincident with the focus of the laser and the axis of theellipsoid is tilted slightly to allow room for further opticalcomponents. Radiation reflected from the ellipsoidal reflector 536 isdirected to its second focal point between the reflector 536 and acollimating lens 537. The collimating lens 537 is placed one focallength from the second focus of the ellipsoidal mirror 536. In thismanner the light exiting the collimating 537 lens will be collimated.

The collimated beam exiting the collimating lens 537 is directed to aquarter wave plate 534, a polarizing beam splitter 538, and two quadrantdetectors 540, 542. The polarizing beam splitter 538 may be a polarizingbeam splitter cube, a Wollaston prism or some another suitablepolarizing beam splitter. In another embodiment detectors 540, and 542may be PIN photodetectors also available from Hamamatsu, Inc. Thesecomponents collect radiation reflected from the surface of wafer 520,and hence may be considered a reflected radiation collection assembly.

Detectors 540, 542 and PMT 532 may have outputs connected to aprocessing module substantially as described in FIG. 1 to process theoutput substantially as described above.

FIG. 6 is a schematic illustration of various optical components of anembodiment of an apparatus for wafer edge inspection. Wafer 620 includesan upper surface 622, a lower surface 624, and an edge surface 626,which may be substantially flat or curved when viewed in across-sectional profile. In the embodiment depicted in FIG. 6, the waferedge surface is curved when viewed in cross-sectional profile.

A surface analyzer assembly 610 is positioned to direct radiation onto asurface of wafer 620. In the embodiment depicted in FIG. 6, surfaceanalyzer assembly 610 includes a laser diode 612 and a focusing lens 614for directing radiation onto a surface of turning mirror 616A. Mirror616A reflects light onto the surface of a spherical or hemisphericalmirror 632. In one embodiment the radiation reflected from mirror 616Amay pass through a Schmidt corrector plate 618A.

Radiation reflected from spherical mirror 632 is reflected onto thesurface 622, and a portion of the radiation incident on surface 622 isreflected back to spherical mirror 632, which reflects the radiationonto turning mirror 616B. In one embodiment the radiation reflected fromspherical mirror 632 onto mirror 616B may pass through a Schmidtcorrector plate 618B.

Radiation reflected from turning mirror 616B passes through collimatinglens 634, quarter-wave plate 636, and onto polarizing beam splitter 638(which is rotated at 45 degrees to the plane of incidence), whichdirects the split beams onto detectors 640, 642. The polarizing beamsplitter 638 may be a polarizing beam splitter cube, a Wollaston prismor some another suitable polarizing beam splitter. In another embodimentdetectors 640, and 642 may be PIN photodetectors also available fromHamamatsu, Inc. These components collect radiation reflected from thesurface of wafer 620, and hence may be considered a reflected radiationcollection assembly.

In one embodiment, scattered light may be collected by removing aportion part of the spherical mirror 632, e.g., in the center of thespherical mirror, and placing a PMT (or avalanche photodiode or PINphotodiode) above this location. Optionally, a collecting lens may beincluded.

In another embodiment one or more of the edge scanning devices describedherein may be combined with another tool for scanning for defects on theflat part of the wafer (top or bottom). Such a combined tool may includethe edge scanning device together with an automation device (e.g., arobot) for handling the wafers and a second tool, possibly within thesame enclosure, for scanning the flat top or bottom of the wafer fordefects. For example an edge inspection device as described herein maybe combined with a Viper 2430 macro defect inspection tool. The edgescanner and the Viper 2430 may share a common robot for handling thewafers as well as a common mechanical platform (e.g., housing). In thismanner, the edge of the wafer may be inspected as well as the flat partwithin a single inspection tool which shares a common robot. The edgescanner described above may be combined with any number of otherinspection or metrology tools to make a device which scans the entiresurface (i.e., top, edge and bottom) for various types of defects.Examples of tools which may be combined with the edge scanner include:SP1, SP2, Viper 2401, Viper 2430, KT 2360, AIT-UV, AIT or any otherinspection or metrology tool.

Reference in the specification to “one embodiment” or “an embodiment”means that a particular feature, structure, or characteristic describedin connection with the embodiment is included in at least animplementation. The appearances of the phrase “in one embodiment” invarious places in the specification may or may not be all referring tothe same embodiment.

Thus, although embodiments have been described in language specific tostructural features and/or methodological acts, it is to be understoodthat claimed subject matter may not be limited to the specific featuresor acts described. Rather, the specific features and acts are disclosedas sample forms of implementing the claimed subject matter.

1. A surface analyzer system, comprising: a radiation targeting assemblyto target a radiation beam onto a surface; and a reflected radiationcollecting assembly that collects radiation reflected from the surface;wherein the reflected radiation collecting assembly comprises a mirrorto collect radiation reflected from the surface.
 2. The system of claim1, further comprising: a first drive assembly to impart linear motionbetween the surface analyzer and a first surface; and a second driveassembly to impart rotary motion between the surface analyzer and thefirst surface about an axis parallel to the first surface.
 3. The systemof claim 1, further comprising a third drive assembly to impart rotarymotion about an axis perpendicular to the surface.
 4. The system ofclaim 1, wherein the reflected radiation collecting assembly comprises acurved collecting mirror to collect reflected radiation.
 5. The systemof claim 4, wherein the collecting mirror is a paraboloid collectingmirror.
 6. The system of claim 4, wherein the collecting mirror is anellipsoidal collecting mirror.
 7. The system of claim 1, wherein thereflected radiation collecting assembly comprises a spherical mirror. 8.The system of claim 1, further comprising a scattered radiationcollecting assembly that collects radiation scattered from the surface9. The system of claim 1, further comprising an analysis module thatanalyzes data generated by radiation scattered from the surface and datagenerated by radiation reflected from the surface.
 10. The system ofclaim 9, wherein the analysis module includes at least one of areflectometer, a scatterometer, a phase shift microscope, amagneto-optical Kerr effect microscope, an optical profilometer, or anellipsometer.
 11. A system to inspect an edge of a wafer, comprising: asurface analyzer assembly comprising: a radiation targeting assemblythat targets a radiation beam onto a surface of the wafer; a reflectedradiation collection assembly that includes a mirror to collectradiation reflected from a surface of the wafer; and means for rotatingthe surface analyzer assembly about an edge surface of the wafer. 12.The system of claim 11, wherein the mirror is a parabolic mirror. 13.The system of claim 11, wherein the mirror is an ellipsoid mirror. 14.The system of claim 11, wherein the reflected radiation collectionassembly comprises a spherical mirror with a Schmidt corrector plate.15. The system of claim 11, further comprising three measuring devicesand pushers, wherein the measuring devices locate the central axis ofthe wafer and align the central axis of the wafer with the central axisof the spindle.
 16. The system of claim 11, further comprising ananalysis module that analyzes data generated by radiation scattered froma surface of the wafer and data generated by radiation reflected from asurface of the wafer.
 17. A surface analyzer system, comprising: aradiation source; a radiation detector; and a spherical mirror to directradiation from the radiation source onto a surface and to directradiation reflected from the surface toward the radiation detector. 18.The system of claim 17, further comprising a first radiation targetingassembly to direct radiation from the radiation source to the sphericalmirror, the radiation assembly comprising: a focusing lens; a mirror;and a Schmidt corrector plate.
 19. The system of claim 17, furthercomprising a second radiation directing assembly to direct radiationfrom the surface to the radiation detector, the second radiationassembly comprising: a Schmidt corrector plate; a collimating lens; aquarter wave plate; and a beam splitter.
 20. The system of claim 17,further comprising an analysis module that analyzes data generated byradiation scattered from the surface and data generated by radiationreflected from the surface.
 21. The system of claim 17, wherein theanalysis module includes at least one of a reflectometer, ascatterometer, a phase shift microscope, a magneto-optical Kerr effectmicroscope, an optical profilometer, or an ellipsometer.
 22. A method ofinspecting a wafer, comprising: directing a first beam of radiation ontoa surface; directing a portion of the radiation reflected from thesurface to a radiation detector using a collecting mirror; and analyzinga portion of the radiation received in the detector to determine acharacteristic of the surface.
 23. The method of claim 22, whereindirecting a first beam of radiation onto a surface comprises rotating asurface analyzer assembly about an edge surface of a wafer.
 24. Themethod of claim 22, wherein the collecting mirror comprises a paraboloidmirror.
 25. The method of claim 22, wherein the collecting mirrorcomprises an ellipsoidal mirror.
 26. The method of claim 22, wherein thecollecting mirror comprises a spherial mirror.